Use of a vibratory spiral elevator for crystallizing and/or drying of plastic pellets

Abstract

A method and system for processing a polymer includes providing a molten polymer and processing the polymer into malleable components for delivery to a spirally wound conveying surface. Vibratory forces may be utilized to urge the components along the length of the conveying surface as they undergo crystallizing or drying or crystallizing and drying. Additional supplemental temperature control may be employed to affect crystallization and/or drying of the components along the conveying surface.

1 . A method of processing a polymer comprising: 
 providing a molten polymer;    processing said polymer into malleable components;    delivering the components to a conveying surface spirally wound about a central axis;    urging the components along the length of the conveying surface; and    crystallizing or drying or crystallizing and drying the components on the conveying surface.    
   
   
       2 . The method of  claim 1 , further comprising: 
 using vibratory forces to urge the components along the length of the conveying surface.    
   
   
       3 . The method of  claim 2 , further comprising: 
 producing the vibratory forces via a drive motor.    
   
   
       4 . The method of  claim 3 , wherein the drive motor is coupled to the conveying surface.  
   
   
       5 . The method of  claim 1 , further comprising: 
 applying supplemental temperature control to the components along a length of the conveying surface to affect crystallizing or drying or crystallizing and drying of the components.    
   
   
       6 . The method of  claim 5 , wherein the supplemental temperature control includes heating or cooling or both.  
   
   
       7 . The method of  claim 5 , further comprising: 
 utilizing one or more heat transfer media to provide supplemental temperature control to the components.    
   
   
       8 . The method of  claim 7 , wherein the heat transfer medium is selected from the group consisting of air, water and oil.  
   
   
       9 . The method of  claim 1 , further comprising: 
 delivering the crystallized and dried components directly from the conveying surface to receiving equipment.    
   
   
       10 . The method of  claim 9 , wherein the receiving equipment is selected from the group consisting of a silo, a bin and a conveying system.  
   
   
       11 . The method of  claim 1 , wherein the components are delivered to the conveying surface at a temperature of approximately 140° C.  
   
   
       12 . The method of  claim 1 , wherein the processing step further comprises: 
 subjecting the polymer to an underwater pelletizer to form pelletized components;    mixing water with the pelletized components to form a water and pellet slurry;    filtering agglomerates from the water and pellet slurry; and    removing excess moisture from the water and pellet slurry.    
   
   
       13 . The method of  claim 12 , wherein the polymer is subjected to the underwater pelletizer at a temperature of approximately 280° C. and the water mixed with the pelletized components has a temperature of approximately 90° C.  
   
   
       14 . The method of  claim 12 , wherein the step for removing excess moisture includes de-watering the water and pellet slurry and subjecting the de-watered pellets to a dryer.  
   
   
       15 . The method of  claim 13 , wherein the de-watered pellets contain approximately 5% water by mass prior to being subjected to the dryer.  
   
   
       16 . The method of  claim 1 , wherein the components have a dryness of less that 0.05% water by mass and a crystallinity of greater than 30% after said components have been crystallized and dried.  
   
   
       17 . A method of processing a polymer comprising: 
 providing a molten polymer;    processing said polymer into malleable components;    delivering the components to a conveying surface spirally wound about a central axis;    vibrating the conveying surface to urge the components along the length of the conveying surface; and    crystallizing or drying or crystallizing and drying the components on the conveying surface.    
   
   
       18 . The method of  claim 17 , further comprising: 
 producing the vibratory forces via a drive motor.    
   
   
       19 . The method of  claim 18 , wherein the drive motor is coupled to the conveying surface.  
   
   
       20 . The method of  claim 17 , further comprising: 
 applying supplemental temperature control to the components along a length of the conveying surface to affect crystallizing or drying or crystallizing and drying of the components.    
   
   
       21 . A method of processing a polymer comprising: 
 providing a molten polymer;    processing said polymer into malleable components;    delivering the components at approximately 140° C. to a conveying surface spirally wound about a central axis;    vibrating the conveying surface to urge the components along the length of the conveying surface; and    crystallizing or drying or crystallizing and drying the components on the conveying surface to produce a dryness of less that 0.05% water by mass and a crystallinity of greater than 30%.    
   
   
       22 . The method of  claim 21 , further comprising: 
 applying supplemental temperature control to the components along a length of the conveying surface to affect crystallizing or drying or crystallizing and drying of the components.    
   
   
       23 . A system for processing a molten polymer comprising: 
 means for processing said polymer into malleable components;    means for delivering the components to a conveying surface spirally wound about a central axis;    means for urging the components along the length of the conveying surface; and    means for crystallizing or drying or crystallizing and drying the components on the conveying surface.    
   
   
       24 . The system of  claim 23 , wherein the means for processing includes using equipment selected from the group consisting of an underwater pelletizer, a strand cutter, a static de-watering device and a centrifugal de-watering device.  
   
   
       25 . The system of  claim 23 , wherein the delivering means comprises a conveyor system.  
   
   
       26 . The system of  claim 23 , wherein the urging means comprises vibratory forces applied to the conveying surface.  
   
   
       27 . They system of  claim 27 , wherein the vibratory forces are produced by a drive motor.  
   
   
       28 . The system of  claim 23 , wherein the means for crystallizing or drying or crystallizing and drying comprises means for applying supplemental temperature control to the components along a length of the conveying surface to affect crystallizing or drying or crystallizing and drying of the components.  
   
   
       29 . The system of  claim 29 , wherein the supplemental temperature control includes heating or cooling or both.  
   
   
       30 . The system of  claim 29 , further comprising: 
 means for utilizing one or more heat transfer mediums to provide supplemental temperature control to the components.